The invention relates to a y-shaped gusset structure of a support frame for vehicles as well as a method for its production.
Various designs of gusset structures for vehicle support frames are known from practical application. The crash safety of the vehicle support frame is decisively determined by its geometry, i.e. by the position of the elements of the support frame—as a rule hollow sections —relative in relation to each other, and by the stiffness of the gusset structures. In particular in the region where the front or rear longitudinal member is connected to the passenger compartment, which region represents a crash zone which is particularly subjected to loads, preferably y-shaped gusset structures are used in order to achieve a favourable distribution of the longitudinal forces, which during a crash act on the passenger compartment. In order to minimise the danger of the hollow sections collapsing in the region of the gusset structure, said gusset structure has to be designed so as to provide maximum stiffness. To this effect, conventional design solutions require the use of additional reinforcement elements; a solution which leads to an undesirable increase in the overall weight of the vehicle support frame. In particular with the use of interior high-pressure metal forming technology, which saves weight due to the lack of welding flanges, adequate rigidity of the gusset structure can only be achieved with the use of support plates. This partly negates the weight gain achieved by this solution.
EP 0 568 251 B1 describes a support frame for vehicles, which support frame comprises several subassemblies based on hollow sections. The hollow sections are interconnected by way of various types of gusset structures in stretched or rectangular positions. The connection of sections which are arranged at right angles in relation to each other, for example the connection between the B-pillar and the lateral sill, is implemented by way of a T-shaped gusset structure. According to an embodiment of such a T-gusset, one end of a first hollow section of rectangular cross section comprises two sections, arranged flush with each other and bent by 90°, with said sections comprising a C-shaped cross section, wherein a second hollow section can be placed against said sections and welded to them.
A gusset structure which is similar to the above embodiment is known from DE 37 26 079 A1. This printed publication describes a door frame construction for utility vehicles, in particular for buses or coaches. The central component of this design is also made up of a T-shaped gusset structure for connecting two hollow sections arranged at a right angle in relation to each other. In this arrangement, the opposing lateral surfaces of one of the hollow sections, at their ends facing the other sections, have been longitudinally cut open in such a way that two U-shaped connection pieces are created which can be formed to constitute a desired transition contour and which can be placed against the section to be connected. In both the above-mentioned printed publications, the respectively described frame structures are largely or exclusively based on T-shaped gusset structures. There is no description of the connection of hollow sections by way of y-gusset structures which are advantageous as far as their crash behaviour is concerned.